mktime Function

Converts local time to a calendar value.

Include

<time.h>

Prototype

time_t mktime(struct tm *tptr);

Argument

tptr

a pointer to the time structure

Return Value

Returns the calendar time encoded as a value of time_t.

Remarks

If the calendar time cannot be represented, the function returns -1 cast as a time_t (i.e. (time_t) -1).

Example

#include <time.h>
#include <stdio.h>

int main(void)
{
  time_t timer, whattime;
  struct tm *newtime;

  timer = 1066668182; /* Mon Oct 20 16:43:02 2003 */
  /* localtime allocates space for struct tm */
  newtime = localtime(&timer);
  printf("Local time = %s", asctime(newtime));

  whattime = mktime(newtime);
  printf("Calendar time as time_t = %ld\n", 
          whattime);
}

Example Output

Local time = Mon Oct 20 16:43:02 2003
Calendar time as time_t = 1066668182